1. Field of the Invention
The invention concerns a solid-electrolyte battery, particularly for the storage of electrical energy, with at least one anode- and one cathode space (electrode spaces), which are connected to one another by ionic conduction through the solid electrolyte and which have collecting and equalizing spaces for the reactants and reaction products respectively.
In order for these batteries to be usable in as many fields of technology as possible, they should exhibit the following characteristics:
First, these batteries must possess a high energy density, i.e. their energy content must be as large as possible with the smallest size and/or weight. Further, the batteries must have a high specific output, they must be able to give high output with the smallest weight and/or volume. Long life is also desirable, i.e. the useful operating lifetime and the number of charge and discharge processes possible (cycling life) must be large. Finally, the materials necessary for making the batteries should be available in sufficient quantity for economical fabrication.
The endurance tests carried out thus far on storage cells or batteries have shown that the mentioned requirements of high specific output and long life or cycling life can not be simultaneously satisfied with the conventional battery construction. Thus it is possible to raise the specific output capacity of such batteries with large charge and discharge current densities, but this simultaneously reduces the lifetime. This is because high current loads and/or current density variations in the solid electrolyte alter its structure and often cause fissures which lead to internal short circuits. If on the other hand the charge and discharge current densities are made smaller, then the solid electrolyte is less loaded and the battery life is extended. Simultaneously, however, its weight and/or size increases so that the specific output is lessened.
The lifetime of such a battery can also be increased by reduction of the operation temperature. This again, however, has the disadvantage that the ionic conductivity of the solid electrolyte decreases and thereby reduces the specific output of the battery or the size of the battery must be increased for the same output.
Added to this is the fact that, in spite of numerous attempts, there has so far been little success in finding suitable materials for the battery case and metal parts incorporated in it which can withstand the reactants and can be made cheaply in sufficient quantity.
2. Description of the Prior Art
A known fuel cell (U.S. Pat. No. 3,300,344), constructed like a solid-electrolyte battery, needs for its fabrication a great number of component parts so that it is large in volume. The specific output is thus correspondingly low.
The sodium-sulfur battery disclosed in German Pat. No. 2,316,336 does indeed exhibit certain improvements in construction, but the main problem of higher energy density paired with higher specific output and long life is not solved.